Generally, the second generation mobile communication means that audio is transmitted and received by being digitized and includes CDMA, GSM or the like. GPRS evolved from the GSM has been proposed. And, the GPRS is the technology for providing a packet switched data service based on the GSM system.
The third generation mobile communication means that images and data can be transmitted/received as well as audio. The 3GPP (3rd generation partnership project) has developed the mobile communication system (IMT-2000) technology and has adopted WCDMA as a radio access technology (hereinafter abbreviated RAT). Thus, the IMT-2000 technology and the radio access technology (RAT) (e.g., WCDMA) are generically called UMTS (universal mobile telecommunication system) in Europe. And, UMTS Terrestrial Radio Access Network is abbreviated UTRAN.
Meanwhile, the third generation mobile communication is evolving into the 4th generation mobile communication.
The fourth generation mobile communication technology has proposed LTE (long-term evolution network) technology in the course of being standardized by 3GPP and IEEE 802.16 technology in the course of being standardized by IEEE. The LTE uses such a terminology as E-UTRAN (evolved-UTRAN).
Meanwhile, in order to enable communication of data, which are generated by machines without user's interference, in the third or fourth generation mobile communication system as well as data generated by a user, the concept of the M2M (machine-to-machine) communication has been proposed.
The M2M communication may mean a method and system for communication between machines without human interference. In particular, the M2M communication means the system that enables the communication between a machine and an information system of a company, the communication between machines (machine-to-machine), the communication between a machine and a mobile communication terminal (e.g., mobile-to-machine, machine-to-mobile, etc.) and the like.
Moreover, the M2M communication may be used when all the sensors, actuators, middleware, software and application, which enable efficiency and quality to be enhanced in a manner that numerous sensors and actuators are linked to each other on a specific business process, are taken together.
The M2M communication is based on the idea that a network connected to machines is able to provide a further meaningful result when the corresponding machines form the network. To this end, various kinds of heterogeneous wire/wireless communication technologies and software technologies need to be combined together.
FIG. 1 is a diagram for one example of M2M communication.
Referring to FIG. 1, a machine 10 is a device equipped with a unique function and includes an electronic device that is communication-connectible. For instance, the machine 10 may include one of a vending machine, a washer, a refrigerator, a health machine and various kinds of sensors. In particular, the various kinds of the sensors may include a water meter, an electricity meter, a gas meter and the like. And, the various kinds of the sensors may include an ozone sensor, a carbon monoxide sensor, a fire sensor, a crime prevention sensor and the like.
The above-configured machine 10 is equipped with a communication function and may be able to perform a communication with a service server 70 via an AP (access point) 30.
In the following description, one example of application of the M2M communication is explained.
First of all, the concept of a smart grid is recently proposed to control community-based resources including power networks, tap water, electricity, gas and the like.
FIG. 2 shows the concept of a smart grid proposed recently and newly.
The smart grid means a next generation power network intending to optimize energy efficiency by exchanging real-time information interactively between a power supplier and a consumer in a manner of applying IT technologies to a power plant, a substation, a power transmission station, a power consumer and the like. Hence, it is able to raise efficiency in a manner that the power supplier and the consumer are interactive.
In order to describe the smart grid, it is necessary to explain a current power system in the first place. It is designed to produce electricity more than that of an actual use amount by 10%. The produced electricity is set suitable for a maximum consumption amount to prepare for a case of overuse. To this end, various power generating equipments are additionally required as well as fuel. Yet, since there is a considerable amount of wasted electricity, it lowers energy efficiency. And, an amount of discharged carbon dioxide increases in the course of burning coal, petroleum, gas and the like.
If the exact amount of necessary electricity is produced or electricity is usable in response to a produced amount of electricity, it is able to use electricity more efficiently while preventing the global warming. To achieve the goals, the smart grid technology is able to provide an electricity used amount, an electricity supplied amount and a state of power line by converging IT technology on the power grid.
If this technology is adopted, a consumer is able to use electricity when electric charges are low. And, an electronic device can be automatically operated during hours of low electric charges.
In aspect of a power producer, since a real-time power use status can be obtained, it is able to adjust a power supply amount flexibly. Since it may be unnecessary to maintain a maximum power amount during hours of less power use, it is able to reduce the wasted electricity. And, the electricity is saved and then supplied during hours of more power use, thereby enabling a flexible operation and management of electricity. Moreover, it is able to prevent malfunction of the power grid due to overload.
A smart meter 60, which is one of the network components of the smart grid, is a device that becomes a point for discriminating users in-between. And, the smart meter 60 enables user's energy supply and demand to be managed, monitored and controlled.
Functions of the smart meter 60 may include electricity reading, demand response commands, pricing information, connect/disconnect commands and the like. The smart meter 60 is connected to home devices such as a refrigerator, a TV, a washer and the like to configure HAN (home area network). And, the smart meter 60 may be connected to a micro-grid.
The smart meter 60 uses Zigbee, Wifi and the like for wireless communications or power line communication (PLC) and the like for wired communications.
The smart meter 60 may be able to perform interactive communications with a supplier or smart meters via smart grid network.
Thus, the smart meter 60 is a representative device for M2M communication.
Although various examples of usages and applications of the M2M communication, it may be able to consider a situation that a plurality of devices basically perform communications with a base station (BS) or an access point (AP) in a long-term period for their status information transmissions and command receptions by wireless. The device configured to perform the M2M communication is stationary at a specific location or has relatively low mobility. The device configured to perform the M2M communication is provided with a limited battery (e.g., small battery capacity) for downsizing and low cost and performs a transmission of data in relatively small size.
Yet, a base station (BS) or access point (AP) according to a related art fails in having a technology suitable for the M2M communication. For instance, it is highly probable that M2M communication devices may perform communications in a long-term period or may simultaneously perform all communications at a time. Hence, as a plurality of smart meters attempt communications during specific hours, it is highly probable that traffics may increase suddenly. However, the base station or access point of the related art fails in being equipped with the technologies suitable for accepting the M2M communications.